Piston ring



July 31, 1945, E. A. KOETHER 2,380,767

PISTON RING Filed Jan. 31, 1941 3 Sheets-Sheet l 7/17/4/ll/Il/Allllii IZmnentoi: Em z'ZAAoef/ver Cittornegs Jul 31, 1945, E. A. KOETHER2,380,767

PISTON RING Filed Jan. 51, 1941 3 Sheets-Sheet 2 18 l'mventor GttornegsJuly 31, 1945. E. A. KOETHER 2,380,767

PISTON RING Filed Jan. 31, 1941 5 Sheets-Sheet 5 I .llllllllll lliihllmnmu Patented July 31, 1945 PISTON RING Emil A. Koether, Baltimore.MIL, asllgnor, by memo assignments, to Koppel-s Company, Inc., acorporation of Delaware Application January 31, 1941, Serial No. 876,884

' 2 Claims. (Cl. 309-44) This invention relates to piston rings andparticularly to oil control rings chiefly intended for use in the lowergrooves of trunk type pistons for internal combustion engines. Suchgrooves have oil drainage ports and the purpose of the invention is toproduce a strong and durable ring suited for use even in narrow ringgrooves and even in small diameter cylinders, yet having two oilscraping edges associated with ample clearance for oil drainage.

In salvaging old engines having worn pistons and cylinders. where thevalue oi the engine fails to justify reboring cylinders and equippingthem with new pistons, a prime eflort is to stop oil pumping." This canbe done by applying oil control rings which are thin as measured in thedirection of the piston axis and which develop substantial expansiveforce when closed to cylinder diameter, so that high unit pressuresbetween ring and cylinder are had. The problem is to secure adequatestrength and expansive force, and still assure free drainage of scrapedoil. Low cost is an important consideration.

To accomplish the desired results the invention makes use of two Spr nsteel split rings, each thin when measured in the direction of thepiston axis and each of substantial radial dimension to afford thedesired expansive tendency. The two rings are of substantial y the sameradial dimensions but one has, at or near its internal margin, either acylindrical or an outward flaring conical flange that extends toward andengages the other ring. The flange is ported or otherwise formed to passoil and is so dimensioned that the two rings, when assembled, fill thering groove except for the usual side clearance. The intervening spaceaflorded by the flange, together with the ports in the flange, cflers alarge capacity oil draining path.

It is important to increase the radial limits of contact between theunflanged ring and the flange of the flanged ring, so that the unflangedring will be supported not merely at its inner margin. but will besustained nearly to its outer margin at least at closely spaced pointsaround the ring. In this way the tilting tendency of each ring may beresisted. The preferred arrangement is to slot or slit the flange andbend out fingers or bows, in which event oil ports are incidentallyformed.

The rings are preferably formed of spring steel and develop inherentexpansive force. However. the use of expanders is desirable. It ispossible to use a single expander which extends approximstely the fullwidth of the groove and. underindicated by the line 3-3 on F18. 1.

lying both rings, reacts outward on both. In

1 some cases, for example where the flange is conical, two expanders canbe used, each individual- 1y reacting only upon a corresponding one ofthe rin s.

Fig. 4 is a view similar to Fig. 3 but in a plane of section indicatedby the line 4-4 on Fig. 1.

Fig. 5 is a view similar to Fig. 1 showing a modification.

Fig. 6 is a perspective view similar to Fig. 2 showing a variant 0! themodification illustrated in Fig. 5.

Figs. 7 and 8 are views similar to Figs. 3 and 4, the planes of sectionbeing indicated by the lines II and H in Fig. 5.

Fig. 9- is a transverse section through a piston showing a furthermodified form of ring in place with a duplex expander.

Fig. 10 is a fragmentary perspective of the two ring components.

Fig. 11 is an elevation of a duplex expander.

Figs. 12 and 13 are sections on the line i2-i2 and ll-l! of Fig. 9.

' In all forms the rings and expanders are preterably formed of springsteel. poses other metals, such for example as bronze. may be used forring components. All parts are produced by mechanical working (forexample.

rolling or drawing) as contradistinguishcd from 1 casting.

In the drawin s the unflanged component of V the ring is shown asmounted on top, that is toward the working space, of the cylinder, andthe flanged component is shown as mounted away from the working spacewith its flange projecting toward the working space. The two componentsare always assembled as shown relatively to each other, but either onemay be positioned toward the working space without materially afl'ectingthe performance of the ring.

Embodiment of Figs. 1 to 4 true circle it reacts outwardpractlcallruniformly around its circumference.

For special pur- "d with the ring Ila.

The flanged ring has a main or flat portion I1 and a flange it at itsinner margin. There is a gap IS. The dimensions of portion llapproximate those of ring Ii. The height of the flange depends on thewidth of the ring groove.

The flange I8 is slotted at intervals, as indicated at 2!, and adjacenteach slot the metal of the flange is stretched outward to form bows 22,which increase the interval between the radial limits of contact betweenthe flange and the plain or flat ring.

A polygonal split expander 28 with edge notches 2! to pass oil (seeFig. 1) is mounted in the ring groove as shown in Figs. 3 and 4. This istypical of any suitable known expander.

In Figs. 3 and 4 25 represents the cylinder wall and 26 the piston, 21the ring groove and 28 an oil drainage port. 7 g

In Figs. 1-4 the slots II are shown as of considerable width. They neednot be much wider than slits but it is convenient to make them sobecause they serve as large capacity oil ports and thus make itunnecessary to form any other ports. The embodiments of Figs. 5-8dlfl'er chiefly in this detail.

Embodiments of Figs. 5-8 inclusive In Figs. 5 to 8, parts which arefunctionally similar to parts shown in Figs. 1 to 4 are given the samenumber with distinguishing letters.

Referring to Fig. 5 it will be observed that instead of forming slots 2|and stretching the ad jacent metal to produce bows 22, the flange Ila isslitted transversely at intervals around its circumierence, and fromeach slit there is an extension which follows the junction 01 the flangeThe eflect is to free fingers 22a which are bent outwardly. leavingintervals Ila which serve as oil ports. This produces a plurality ofoutwardly bent fingers Ila which are in contact with andhence directlysupported by the ring "a.

Avariantoi'this same ideaisshowninlig. 6 in which there are "two sets ofoutwardly bent fingers 22c. the fln'gers of theftwo sets extending inopposite directions around the circumference of the ring. While theintervals between the fingers 22c provide adequate oil porting in mostcases, additional oil porting is suggested in Fig. 8 and may be Providedby the use of notches Me I orslot ports lid, or both.

The particular location of the notches and slots is largely a matter oichoice, the purpose of illustratingtheminl'lg.8beintoindicatepossibilities which may be availed of where additional portingis desired.

The form oi Fig. 5 and the form of Fig. 8 haveincommontheideaoioutwardly bent fingers which engage the ring "a and which increase theradial extent of engagement between the flanged component "a and theflat component Ila. (See Figs. 6, 7 and -8.) It is probablyunnecessarytostatethatwiththerormshowninFig.5andwiththeiormshownin1'ig.8 agfilingllaisassembiedasindicatedinl'lgs.

Embodiments of Figs. 9-43 lntheseflgurespartssimilartopartsinllgs. 1-4aresimilarly numbered with thedistinguishingletterb.

Ring lib is identical with ring ii. The other ring diflers first in theform or flange I lb which at an acute angle to the main portion lib.Thus the flange is conical and flares outward. To extend the outerradial limit of engagement, recourse is had to lobes 22b, best shown inFig. 10, which are produced without the use of slits or slots. Separateoil ports 2 lb are formed as shown. This embodiment makes clear the factthat the oil ports are not necessarily associated with "the fingers orbows of the preceding figures.

, A two-piece expander 23b is used. These expander elements may have oildrain notches 24b. Their proximate edges are serrated and the bends inthe two emanders are staggered, permitting extra width at the bends asshown (see Fig. 11). However, this is only one form of multiple pieceexpander which may be used to advantage with this type of ring. Eachexpander reacts only upon a corresponding ring, permitting accommodationto wear of individual rings. Such selective action of the expanders ispossible because the flare of flange llb keeps the expander fromengaging the 18086.

General discussion of all forms Four embodiments of the main inventiveconcept have been shown and others are possible. These examples areillustrative and not in any sense limiting. While the invention isprimarily intended for use in internal combustion engines,

' in piston ring grooves. said assembly comprising a split ring thin inaxial dimension and of comparatively large radial dimension; and a splitring with a cylinder contacting portion or similar axial and radialdimensions having an integral flange at its inner margin continuousexcept for said split and extending toward and engaging the proximaterace oi the first-named ring tospacetheringsandtoflxtheover-allaxialdimension of the assembly whileleaving the two rings tree to expand and contract independently of oneanother, said flange having spaced outwardly deflected portions at thearea of such enagement. the thickness oi said flange pproximating thethickness of the cylinder contacting portion upon which it is formed.

'2. An oil control piston-ring assembly for use in piston ring grooveshaving oil drainage ports, saidassemhlycomprisingasplitringthinin axialdimension and of comparatively large radial dimension; a mlit ringhaving a cylinder contactingportionolsimilaraxialandradial dimensionsandhavingatitsinnermsrginaported flange of a thickness approximating saidaxial dimension, the flange being continuous except for said split andextending toward and engaging theproximate face or the'flrst-nsmed ringto spacetheringsandflxtheoveraliaxlaldimensionottheassemblmtheedgeotsaidflangehav- 118 deflected Portionsserving to increase the radial range 0! ngagement, while leaving the tworings tree to expand and contract independently of-one another: andyeilding means for expanding laid rings. 1

IIIL A. KOITHIR.

